Drying drum



Feb. 20, 1951 H. E. NEUBAUER 2,542,287

DRYING DRUM Filed Nov. 6, 1945 2 Sheets-Sheet 1 INVENTOR.

M a %m ATTOFNZ'YS Feb..20, 1951 H. E. NEUBAUER 2,542,287

DRYING DRUM Filed Nov. 6, 1945 2 Sheets-Sheet 2 ATTORNEYS 4 BY IIIII IIing a revolution; and with which removal of the condensed steam will notbe materially interferred with.

Other objects and advantages will be apparent from the followingdescription of an embodiment of the invention, and the novel featureswill be particularly pointed out hereinafter in connection with theappended claims.

In the accompanying drawings:

Fig. 1 is a longitudinal, sectional elevation through a dryer drumconstructed in accordance with this invention and illustrating anembodiment thereof;

Fig. 2 is the longitudinal, sectional elevation through the drum alone,but with parts of slightly different proportions than in Fig. 1; and

Fig. 3 is a transverse, sectional elevation through the same, thesection being taken approximately along the line 33 of Fig. 2.

In the illustrated embodiment of the invention and referringparticularly to Fig. l, the improved dryer drum includes a generallycylindrical wall I having at its ends inturned radial flanges 2. Aclosure 3 is secured to one end of r the wall I, and extends across theopening at that end of the wall. so as to overlap with the flange 2 andtightly close that end of the wall. This closure 3 may be detachablysecured to the flange 2 in any suitable manner, such as by screws Iwhich pass through the periphery of the clo ure 3 into the flange 2. Atthe opposite end of the cylindrical wall I is a somewhat similar closure5 which is similarly secured to the other flan e 2 in the ame manner,such as by screws 4. Thus the cylindrical wall I is closed at both endsby the closures 3 and 5 to form a closed, hollow drum that is generallycylindrical in shape.

The closures 3 and 5 have bearing trunnions or bosses 6 extending fromthe ends thereof so that the drum may be rotatably mounted in suitablebearings, not shown.

One of these trunnions 6, such as the one on the closure 5, is tubularand open at both ends so as to provide an axial pa sage I opening intothe chamber 8 of the drum formed by the wall I and closures 3 and 5. Thetrunnion 6 on closure 3 is closed at its outer end. A tube 9 is disposedin the passage I and is held against rotation relatively to the adiacenttrunnion through which it passes. A stufiing box or gland It is providedon the outer end of the bearing a of closure 5 around the tube 9 so asto close the passage I except for that through the tube 9. This tube 9extends into the chamber 8 and there terminates in an open end II. Theouter end of the tube 9 is closed by a disk I2, but adjacent the closedend the tube is provided with a laterally extending boss I3 into which apipe from a source of steam may be connected. Within the tube 8 is apipe I having an external diameter smaller than the internal diameter ofthe tube 9, and extending from outwardly beyond the stuffing box I!)along the tube 9 into the chamber 8 and there joined to a detachable,but downwardly extending pipe I5, which, at its lower end, extends intoclose proximity to the inner periphery of the wall I. This lower end ofthe pipe I5 is open, and the outer end of the pipe I4 is suitablyconnected to a steam trap or other source of suction, or to a siphondevice so that a suction will be created at the lower end of the pipe I5within the chamber 8 of the drum to remove from the drum the steamcondensing therein and collecting as a pool in the bottom part of thedrum.

The tube 9 and pipe I4 are held against rotation so that the pipe IEwill always extend to the bottom of the drum while the drum is rotating.Suitable means, not shown, is mounted on the hearing B'of closure 5 toturn the drum at the desired rate. These drums may be used singly or.

in groups.

The wall I of the drum is provided with a plurality of internal,endless, annular rings or ribs I6 which are formed integrally with, orare welded to, the inner peripheral surface of the wall i and extendradially but only partially across the chamber 8. These ribs I8 aredisposed side by side but spaced apart at intervals along the length ofthe drum, and are peripherally continuous along the wall I.

The condensed steam will normally collect in a poolalong the bottom partof the drum, and when the drum is rotating it will be spread as a filmalong the surface of the drum in a peripheral direction to an extentdepending upon the speed of rotation and the amount of liquidaccumulating in the bottom of the drum. The condensed liquid will flowtowards the portion of the drum where it is removed through the pipe i5.In order to facilitate the movement toward the pipe I5 of the liquidcollecting in the bottom part of the drum, and keep the depth of thepool to a minimum, the ribs I5 are each preferably provided with one ormore ports or apertures I'a" disposed in close proximity to the innerperiphery of the wall I. The condensed liquid may thus pass throughthese ports or apertures to pipe I5 for removal, which reduces theextent to which the film of liquid spreads out alongthe inner peripheryof the drum due to the rotation of thedrum. In other words the ports orapertures I'd make it possible to keep the depth of the pool ofcondensate in the bottom part of the drum to a minimum. There arepreferably a plurality of such ports or apertures IT in each rib, spacedapart in a direction peripherally of the drum, as shown clearly in Fig.3, so that the condensate in the bottom part of the drum will have thedesired freedom of movement toward the inlet end of the pipe I 5 whilethe drum is rotating. Only one suction pipe is required, and yet thepool of condensate in the bottom part of the drum may be ke t to aminimum depth.

Each of the ribs preferably also terminates along its inner edge in alateral flange I8, preferably a double flange extending in bothdirections from the inner periphery of the rib, generally parallel tothe axis of rotation of the drum. These flanges I8 with the rib providea very rigid stiffening reinforcement for the wall I of the drum, andsubstantial face area in contact with the steam, and when the doubleflange is used, such a reinforcement is T-shaped in cross section withthe head of the T forming the inner periphery of the rib.

The T-shaped cross section, together with the portion of the drum wallto which it is attached, corresponds to the cross section of an I-beamwhich is recognized as a structure having maximum resistance todeflection and distortion with a minimum of weight, and of depth of therib. As an illustration of the value of the T-shaped rib with the headof the T spaced from the drum surface, a comparison of the resistance todeflection of a drum with stiffening ribs of difierent types may beeasily made by tests upon a hoop of the same width or depth as the ribor T section, undera load applied to the hoop at two opposite points.Under such tests it can be estab lished that the T-shaped reinforcingrib will inamazon 5.? crease the resistance 'to'dis't'ortion orstifiness oi the hoopby about twelve. times thatof. a hoop with no rib,whereas a plain rib of the same width and depth, but without the Tflange on its inner periphery; will increase the strength of the hoop byabout fountimes that of a hoop with no rib.

In Fig. 2 the drum is similar. tor that shown? in Fig. 1, but is of fulllengthhto show moreseitectively the 1 plurality of ribs...- spacedalong. .--the same. Similar parts are given similar referencecharacters.

Fig; sillustrates more effectively than inFig. 1., the spacing.arrangement of the apertureswll along the rib..

It will be observed thatthe reinforcing ribs extend into the chamber ofthe: drum :wh'eretheir massis in goodv thermal relation:with'zthezsteamiwhich "is usually at: a constant: temperature,

which facilitates transfer of heat=from the steam" to the peripheralwall by conduction. Consequently heat loss by conduction to the shell isreduced to a minimum, and the stiifening rib itself is not subject tothermal deformation with the shell which is necessarily exposed totemperature variations or differentials. Thus the stifiening rings orribs are maintained at an approximatel constant temperature by asubstantially total immersion in the body of steam or other heatingfluid.

In double drum dryers as heretofore made without the stiffening ribs.the distortion and irregularity in the surface of the drum becameprogressively worse with the passing of time, and it is impractical tomake the peripheral wall of the drum sufiiciently thick to avoid suchdistortion. Drums having the internal, annular endless stiffening ribsin accordance with this invention, after operation for a substantialperiod of time in which appreciable distortion would appear if the drumswere not stiifened with these ribs, have been found to have no materialdistort on and no material decrease in their drying capacity.

Standard drums of the same wall thickness without the reinforcing ribswere a continuous source of trouble, and distortion therein was suchthat a variation in clearance between high and low spots on the drums inmuch less than a year, would often amount to from .010 to .050 inch. Thecapacity of such unstiifened drums was reduced as much as 50% becausethe drums then had to be forced closely together to reduce to a minimumthe clearance at the low spots. The drum speed had to be reduced toprevent wet spots on the drums and to remove the moisture from theheavier parts of the film. On the high spots, there would either be nofilm at all, or a very thin film, and when heat sensitive products weredried, there was considerable overdrying, loss of quality of theproduct, and sometimes scorching. In order to maintain production whenusing drums without stiffening ribs and operating under criticalconditions, it was necessary to resurface the outside surfaces of thedrums at frequent intervals.

These difiiculties appear to be fully overcome when the drums areprovided with the internal stiifening ribs in accordance wtih thisinvention, so thatoperation of the improved stiffened drums even undercritical conditions for relatively long periods of time, withoutresurfacing, appears to be possible. When the improved drums are used todry a traveling web, of paper as in a paper mill, it is important thatthere be a rapid transfer of heatrfrcmzthaisteam admittedatorthe drumztothe. outer peripheral drumrsurface'sand'. the' ribsi act asnvanes. whichprovide somewhat betterfheat' transfer from: the. steam to the wallcontactwitlr'the': moving web, as: well as: reducing or'eliminatingdistortion of the; drum such as==would1re+ quire resurfacingOfxthfdl'lllfl surface;

It :will he: understood that various changes tin the details...materials andiarrangem'entsief parts; whichlhave'been herein describedand'illlustrated in order 1' t I explain the. nature? of theiiinvention;mayzbe. madebythose skilled in i the art within the principleandiscop'eiofthe invention, as"ex-= prssediinithe appended claims:

I claim:

1. Inia dryer iofi thewtypietin which steam "is ad"- mitted :to theinterior of a hollow, rotatable, closed: drum to heat the exteriordrying surface thereot-andfrom whichcondensatioin is removed by a pipeextending intcthe chamber of the drum and-'zdownwardly therein intoclose proximity to the bottom portion of the periphery of the drum, thatimprovement which comprises an annular T-shaped rib within andintermediate the ends of the drum, having the base and of the leg of theT rigidly attached to the inner periphery of the drum and extendingradially of the drum, with the head of the T forming the inner peripheryof the rib, the leg of the T being apertured from face to face, and thehead of the T being radially nearer the axis of rotation of the drumthan the opening of said pipe within said drum, the space at each sideof the rib being unobstructed, whereby When the drum is internallyheated by steam and the condensed steam is removed through said pipe,the flange formed by the head of the T will b entirely in an atmosphereof steam so as to remain at a relatively constant temperature and willresist substantial distortion of the peripheral wall of the drum.

2. An axially elongated dryer element, which comprises a hollow drumhaving a cylindrical peripheral shell and end walls closing andsupporting the shell, means mounting the drum for rotation about thelongitudinal axis of said shell, means for delivering steam to theinterior of the drum, a non-rotatable pipe entering the drum through anend wall thereof and along said axis, and within the drum having an openinlet end close to the bottom of the drum, and a plurality of annular,T-shaped ribs on the inner periphery of said shell, spaced apartlengthwise of the drum, each rib having its leg apertured from face toface and rigidly attached at its base to, and peripherally continuouswith, the inner peripheral surface of said shell, with the head of the Tforming the inner periphery of the rib, extending in a directionlengthwise of the shell, and disposed nearer the axis of rotation of thedrum than said open end of said pipe, the space between the ribs andbetween the ribs and end walls being unobstructed, whereby when the drumis internally heated by steam and the condensed steam is removed throughsaid pipe, the flange formed by the head of the T will be entirely in anatmosphere of steam so as to rem'iain at a relativel constanttemperature and. will resist substantial distortion of the peripheralwall of the drum.

3. An axially elongated dryer element, which comprises a hollow drumhaving a cylindrical peripheral shell and end walls closing andsupporting the shell, means mounting the drum for rotation about thelongitudinal axis of said shell, means for delivering steam to theinterior of the drum, a non-rotatable pipe entering the drum through anend wall thereof and along said axis, and within the drum having an openinlet end close to the bottom of the drum, and an annular ribdisposedwithin and intermediate of the ends of the interior of the drum,rigidly connected to the inner circumferential Wall of the shell, andextending therefrom towards the axis of rotation of the drum; the ribbeing apertured from face to face at a plurality of intervals along saidshell and terminating at its inner periphery in a "lateral flange thatextends parallel to and is concentric with the axis of rotation of thedrum, the flange being nearer said axis of rotation than said inletopening of said pipe whereby when the drum is internally heated by steamand the condensed steam is continuously removed through said pipe, saidflange of the rib will be subject to a substantially uniform temperatureand will resist substantial deformation of the shell.

HERMAN E. NEUBAUER.

REFERENCES CITED The following references are of record in the file ofthis patent: V

UNITED STATES PATENTS Number Name Date 134,786 Collier Jan. 14, 1873666,477 Hunting Jan. 22, 1901 700,776 Hunting V May 27, 1902 1,116,196Zierden Nov. 3, 1914 4 FOREIGN PATENTS Number Country Date 160,380 GreatBritain Mar. 24; 1921 OTHER REFERENCES Pocket Companion for Engineers,Architects and Builders, 19th Edition, published January 1, 1917 byCarnegie Steel Company. Copy available in Division 49.

